Smelting method for metallurgical electric-furnace

ABSTRACT

The present disclosure provides a metallurgical electric furnace, and a smelting method for the metallurgical electric furnace. The metallurgical electric furnace includes a furnace body, an oxygen lance and a coal lance, wherein the furnace body is provided with a furnace chamber; the oxygen lance is located on a side wall of the furnace chamber and is used for blowing oxygen into the slag promoting the smelting process, and the outlet of the oxygen lance is higher than the slag; and the coal lance is located on the side wall of the furnace chamber beside the oxygen lance and is used for spraying coal into the slag, and the outlet of the coal lance is higher than the slag.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the priority of Chinese Application No.201610515542.1, filed in the Chinese Patent Office on Jul. 1, 2016, andentitled “SMELTING METHOD FOR METALLURGICAL ELECTRIC-FURNACE”, theentire contents of which are herein incorporated by reference.

TECHNICAL FIELD

The present disclosure relates to the field of metallurgy, and moreparticularly to a metallurgical electric furnace and a smelting methodfor the metallurgical electric furnace.

BACKGROUND

Oxygen has been widely used in the metallurgical industry and has beenvery successful, wherein the oxygen has been successfully used insteelmaking converters, has been successfully applied to the melting ofscrap steel in electric arc furnaces, and is combined with coalinjection to produce foaming slags to improve the efficiency, which arevery mature and widely used process technologies. The oxygen has beensuccessfully applied to the nonferrous metallurgy since the 1970s. Thereare two famous types: firstly, Ausmelt developed by Outotec has beenused for smelting lead, zinc, nickel, copper, tin and other minerals,and secondly, ISASMELT developed by MIM and CSIRO in Australia has alsobeen successfully applied to the smelting of non-ferrous metals. Formore than a decade, RIO TINTO has also successfully developed theHISMELT technology for ironmaking, which has also been commercialized,but it has not been widely used in the ironmaking industry. Recently,the Russian company Technologiya Metallov published its Project Magma onits website to explain the oxygen blowing and coal spraying technology,which can be applied not only to the non-ferrous metals, but also can beapplied to ferrous metals

(Ferrous Metallurgy)

In the current metallurgical electric furnaces (such as a titanium slagelectric furnace), the chemical energy has never been applied by virtueof the oxygen blowing and coal spraying technology to reduce theconsumption of electric energy and to improve the efficiency ofsmelting. The present disclosure aims at promoting the oxygen blowingand coal spraying technology to such electric furnaces.

SUMMARY

To this end, the objective of one aspect of the present disclosure is toprovide a metallurgical electric furnace.

The objective of another aspect of the present disclosure is to providea smelting method for the above metallurgical electric furnace.

In order to achieve the above objectives, the embodiment of one aspectof the present disclosure provides a metallurgical electric furnace,including: a furnace body provided with a furnace chamber; an oxygenlance located on a side wall of the furnace chamber and used for blowingoxygen into slag promoting the smelting process, wherein the outlet ofthe oxygen lance is higher than the slag; and a coal lance located onthe side wall of the furnace chamber and used for spraying coal into theslag, wherein the outlet of the coal lance is higher than the slag.

In the metallurgical electric furnace provided by the above embodimentof the present disclosure, especially in the metallurgical electricfurnace operated by an open arc, the outlet of the oxygen lance and theoutlet of the coal lance are higher than the upper surface of the slag,the O₂ is blown into the slag from top to bottom by the oxygen lance,the low-valent reduced state substance in the slag is oxidized to ahigh-valent oxidation state substance, a large amount of chemical energyis released in the oxidation process, the temperature of the slag isincreased, the released chemical energy can effectively melt the feed,meanwhile, the coal particles are also injected into the slag from topto bottom through the coal lance, the carbon in the coal reduces thehigh-valent oxidation state substance to a low-valent reduced state,when the high-valent oxidation state substance is reduced by the carbon,CO is released, meanwhile, the reduction reaction is endothermic, andthen the energy released by the oxidation of the reduced state substanceis also supplied to the reduction reaction; in the slag, due to theexistence of the O₂, the O₂ may also cause a combustion reaction withthe CO and C, the heat of combustion which is produced by the combustionreaction can raise the temperature of the slag so as to provide heat forthe melting of the feed, and can also provide energy for the reductionreaction, in this way, both the chemical energy released in theoxidation reaction and the energy released in the combustion reactioncan be used for the smelting of the feed, so that, in addition toelectrical energy, chemical energy can also provide a large amount ofenergy for the smelting process, thereby increasing the total poweravailable for smelting, and thus improving the productivity andefficiency, and it is especially effective for the slag with a highmelting point, so that the consumption of electric energy is reduced.

In the present solution, the oxygen lance and the coal lance are botharranged above the slag, the O₂ and the coal particles are blown intothe slag from top to bottom, and is away from the furnace lining, sothat the damage to the furnace lining is reduced, and the service lifeof the furnace lining is prevented from being shortened. As the O₂ isblown from top to bottom and inclines toward a direction away from theinstallation position of the oxygen lance on the side wall of thefurnace chamber, that is, the spraying direction of the O₂ faces to theopposite side of the installation position of the oxygen lance on theside wall of the furnace chamber, the coal particles is also sprayedfrom top to bottom and inclines toward the direction away from theinstallation position of the coal lance on the side wall of the furnacechamber, that is, the spraying direction of the coal particles faces tothe opposite side of the installation position of the coal lance on theside wall of the furnace chamber, so that the slag flows toward theopposite side of the installation positions of the oxygen lance and thecoal lance on the side wall of the furnace chamber, but is very far awayfrom the furnace lining, in this way, the generated influence is low,and the integrity of the furnace lining can be protected.

Specifically, using an example that the reduced state substance in theslag is Me₂O₃, the chemical reactions occurred in the slag during theoxygen blowing and coal spraying include:

Me₂O₃+0.5O₂=2MeO₂  (1)

2MeO₂+C=Me₂O₃+CO  (2)

CO+0.5O₂=CO₂  (3)

O₂+C=CO₂  (4)

After the O₂ is blown in, the reaction (1) occurs, the O₂ oxidizes theMe₂O₃ into MeO₂, the oxidation reaction is an exothermic reaction, and alarge amount of chemical energy is released in the reaction for smeltingof the feed; after the coal particles is injected, the reaction (2)occurs, the carbon reduces the MeO₂ into Me₂O₃, meanwhile, releases CO,the reaction (2) is an endothermic reaction, and the chemical energyreleased in the reaction (1) is further used for providing energy forthe reaction (2) in addition to smelting the feed; and the O₂ in theslag may also cause the combustion reactions (3) and (4) with the CO andC, a part of the heat of combustion is released into the slag forsmelting the feed and being supplied to the reaction (2), as thereaction (1), the reaction (3) and the reaction (4) are all exothermicreactions, and the chemical energy released in the reactions is added tothe electric energy, thereby improving the total smelting power andreducing the consumption of electric energy. At the same time, a largeamount of CO is released in the reaction (2) to form bubbles, whichswells the slag into foam slag, and the formation of the foam slag isfavorable for the blowing of the O₂.

The electric furnace of the present disclosure is fixed, the feed issupplied unceasingly, when the molten iron reaches a certain liquidlevel, a molten metal outlet is opened to release the molten metal, thefeed is supplied as usual, and the oxygen and coal are blown and sprayedas usual. After a certain amount of the molten metal flows out, themolten metal outlet is blocked by a blocking machine, after a period oftime, when the slag level is too high, a slag opening is opened todischarge the slag, the feed is supplied as usual, and the oxygen andcoal are blown and sprayed as usual.

In addition, the metallurgical electric furnace provided by the aboveembodiment of the present disclosure further has the followingadditional technical features:

In the above technical solution, preferably, the metallurgical electricfurnace includes a plurality of oxygen lances that are uniformlydistributed along the side wall of the furnace chamber; and a pluralityof coal lances that are uniformly distributed along the side wall of thefurnace chamber; wherein the oxygen lances are located below the coallances, or the oxygen lances and the coal lances are located at the sameheight on the side wall of the furnace chamber.

In a specific embodiment of the present disclosure, the oxygen lancesare located below the coal lances. Preferably, the number of the oxygenlances is equal to the number of the coal lances, the coal lances arelocated right above the oxygen lances, the coal lances and the oxygenlances are arranged in an above-and-below pattern.

In another specific embodiment of the present disclosure, the oxygenlances and the coal lances are located at the same height on the sidewall 11 of the furnace chamber 1, and are arranged next to one anotherin an alternate pattern.

Preferably, the plurality of oxygen lances are uniformly distributedalong the circumferential direction of the side wall of the furnacechamber and are located at the same height on the side wall of thefurnace chamber; and the plurality of coal lances are uniformlydistributed along the circumferential direction of the side wall of thefurnace chamber and are located at the same height on the side wall ofthe furnace chamber.

Preferably, a coal lance and an oxygen lance can be placed in the samecooling jacket, and the distance between the injection points of thecoal lance and the oxygen lance in a molten pool is not less than 300mm.

In the above embodiment, the oxygen lance and the coal lance are locatedabove the molten pool, and the O₂ and the coal particles are blown intothe furnace chamber 1 from top to bottom, the injecting velocity of theO₂ is supersonic to penetrate through the foam slag, the coal can alsobe injected into the molten pool, the plurality of oxygen lances areuniformly distributed on the side wall of the furnace chamber to balancethe mechanical stirring caused by each lance. In such a way, thechemical energy released by the oxidation of the reduced state substancein the slag is uniformly distributed, and thus the uniformity of thefeed distribution in the furnace chamber can be improved; and theplurality of coal lances are uniformly distributed on the side wall ofthe furnace chamber, so that the conversion rate of reducing thehigh-valent oxidation state substance into the low-valent reduced statesubstance is improved.

Preferably, the oxygen lance and the coal lance are installed on theside wall of the furnace chamber, penetrate through a refractorymaterial and enter the furnace chamber.

In the above technical solution, preferably, the metallurgical electricfurnace further includes a spray tube, the spray tube is located on theside wall of the furnace chamber above the oxygen lances and used forspraying a hydrocarbon into a furnace freeboard, and the outlet of thespray tube is higher than the slag.

In the above embodiment, a part of the electrical energy and thechemical energy is applied to the reaction (2), the CO produced by thereaction (2) enters the furnace freeboard, and the CO carries a largeamount of energy, a part of the heat of combustion released by thereactions (3) and (4) is used for smelting the feed and the reaction(2), a part of the heat of combustion heats up gases (CO, CO₂, O₂) andenters the furnace freeboard to serve as a heat source for the pyrolysisgasification of the hydrocarbon to generate coal gas, therefore thepresent disclosure generates the coal gas while improving the totalpower of the smelting, and avoids the waste of energy contained in theflue gas.

The furnace freeboard is also known as a freeboard, which refers to aspace above the molten pool and below a furnace roof.

Specifically, the hydrocarbon causes the following reactions in thefurnace freeboard:

C_(n)H_(m) =nC+m/2H₂  (5)

2C_(n)H_(m)+CO₂=2(n+1)CO+mH₂  (6)

C_(n)H_(m) +nH₂O=nCO+(n+m/2)H₂  (7)

C+CO₂=2CO  (8)

C+H₂O=H₂+CO  (9)

As the space of the furnace freeboard is limited, the reactions (5),(6), (7), (8), (9) may not reach chemical equilibrium, and the finaltemperature and gas composition depend on the dynamic balance of thesystem.

Preferably, a plurality of uniformly distributed spray tubes is arrangedon the side wall of the furnace chamber.

In the above technical solution, preferably, the spraying direction ofthe hydrocarbon into the furnace freeboard is tangential to the sidewall of the furnace chamber. Preferably, the hydrocarbon is sprayedhorizontally into the freeboard.

The embodiment of the second aspect of the present disclosure provides asmelting method for the metallurgical electric furnace according to anyone of the above embodiments, wherein the slag includes a reduced statesubstance capable of being oxidized by O₂, and the smelting methodincludes: blowing oxygen into the slag via an oxygen lance so as tooxidize the reduced state substance to an oxidization state substance;and spraying coal into the slag through a coal lance so as to reduce theoxidized oxidization state substance.

According to the smelting method provided by the above embodiment of thepresent disclosure, the O₂ is blown into the slag from top to bottom tooxidize the low-valent reduced state substance in the slag into ahigh-valent oxidation state substance, a large amount of chemical energyis released in the oxidation process to effectively smelt the slag,meanwhile, the coal particles are also sprayed into the slag from top tobottom to reduce the high-valent oxidation state substance to alow-valent reduced state, CO is released at the same time, the reductionreaction is an endothermic reaction, the energy released by theoxidation of the reduced state substance is also supplied to thereduction reaction; and in the slag, due to the existence of the O₂, theO₂ may cause a combustion reaction with the CO and C, the heat ofcombustion of the combustion reaction can raise the temperature of theslag so as to provide heat for melting of the feed, and can also provideenergy for the reduction reactions, in this way, the chemical energyreleased in the oxidation reaction and the energy released in thecombustion reaction can be used for melting of the feed, in addition toelectrical energy in the smelting process, the chemical energy can alsoprovide a large amount of energy for the smelting process, therebyincreasing the total available power for smelting, and improving theproductivity and efficiency, (it is especially effective for the slagwith a high melting point) and the consumption of electric energy isreduced.

In the above technical solution, preferably, the depth of the oxygenblown into the slag does not exceed one-half of the thickness of theslag.

In the above technical solution, preferably, the depth of the oxygenblown into the slag is within the range of one-third of the thickness ofthe slag to one-half of the thickness of the slag.

In the above embodiment, for different slag systems, the ratios of thedepth of the oxygen blown into the slag to the total thickness of theslag are different, if the slag system needs to be controlled at a verylow oxygen potential to reduce the metal oxides to be recovered, thedepth of the oxygen blown into the slag is within the range of one-thirdof the height of the slag bath to two-thirds of the height of the slagbath, and the coal particles can be sprayed deeper, however, notreaching the metal bath underneath the slag, to ensure the low oxygenpotential.

In the above technical solution, preferably, the coal is anthracite orbituminous coal.

In the electric arc furnace steelmaking, only the anthracite or coke canbe used, and the bituminous coal cannot be used. However, the anthraciteor bituminous coal can be used in the present application. Of course,the coke can also be used in the present application.

In the above technical solution, preferably, after injecting the coalparticles into the slag through the coal lance, the method furtherincludes: blowing a hydrocarbon into the furnace freeboard through aspray tube.

In the above embodiment, the hydrocarbon is blown into the furnacefreeboard horizontally, the energy carried by the CO released by theoxidation reaction, the chemical energy generated by the combustionreaction of CO and O₂, and the chemical energy generated by thecombustion reaction of C and O₂ can be used as the heat source for thepyrolysis gasification of the hydrocarbon, so that a coal gas isgenerated in the furnace freeboard. In the above technical solution,preferably, the hydrocarbon includes natural gas or light oil. Ofcourse, methane gas and solid bituminous coal and the like sprayed intothe furnace freeboard can be converted into the coal gas, thetemperature of the gases (CO, CO₂, H₂, H₂O) generated in the molten poolis extremely high (the temperature is greater than 1700° C.), and thegases contain a large amount of heat, which enters the furnacefreeboard, the above hydrocarbon is sprayed into the freeboard to causeendothermic chemical reactions with the CO₂ and H₂O so as to be crackedinto the coal gas. In such a way the furnace roof can be cooled by theseendothermic reactions.

In the above technical solution, preferably, while spraying thehydrocarbon into the furnace freeboard through the spray tube, themethod further includes: spraying liquid water and/or gaseous water intothe furnace freeboard through the spray tube.

In the above embodiment, in order to increase the content of hydrogen inthe coal gas, a small amount of water may be sprayed while spraying thehydrocarbon. Of course, an additional spray tube can also be arranged onthe side wall of the furnace chamber for spraying the water.

Additional aspects and advantages of the present disclosure will becomeapparent in the following description or are understood via the practiceof the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or additional aspects and advantages of the presentdisclosure will become apparent and readily understood from thefollowing description of embodiments in combination with drawings,wherein:

FIG. 1 is a structural schematic diagram of a metallurgical electricfurnace in an embodiment of the present disclosure, wherein an arrow ata site A represents the blowing direction of oxygen into slag, and thearrow at a site B represents the spraying direction of coal particlesinto the slag;

FIG. 2 is a schematic diagram of an overlooking structure of themetallurgical electric furnace as shown in FIG. 1, wherein the arrow ata site C represents the spraying direction of oxygen and coal particlesinto the slag;

FIG. 3 is a schematic diagram of an overlooking structure of ametallurgical electric furnace in an embodiment of the presentdisclosure, wherein the arrow at a site D represents the blowingdirection of a hydrocarbon into a furnace freeboard.

The corresponding relationship between reference signs and componentnames in FIGS. 1 to 3 is as follows:

1 furnace chamber, 11 side wall, 12 electrode, 13 slag, and 14 moltenmetal.

DETAILED DESCRIPTION

In order that the above objectives, features and advantages of thepresent disclosure can be understood more clearly, the presentdisclosure will be further described in detail below with reference tothe drawings and specific embodiments. It should be noted that theembodiments in the present application and the features in theembodiments may be combined with each other without conflict.

In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the present disclosure, butthe present disclosure may be practiced otherwise than as describedherein, therefore the protection scope of the present disclosure is notlimited by the specific embodiments disclosed below.

A metallurgical electric furnace and a smelting method for themetallurgical electric furnace according to some embodiments of thepresent disclosure are described below with reference to the drawings.

As shown in FIGS. 1 and 2, a metallurgical electric furnace providedaccording to some embodiments of the present disclosure includes afurnace body, an oxygen lance and a coal lance. The furnace body isprovided with a furnace chamber 1; the oxygen lance located on a sidewall 11 of the furnace chamber 1 and used for blowing oxygen into slag 3promoting the smelting process, wherein the outlet of the oxygen lanceis higher than the slag 3; and the coal lance is located on the sidewall 11 of the furnace chamber 1 beside the oxygen lance and used forinjecting coal particles into the slag 3, wherein the outlet of the coallance is higher than the slag 3.

In the metallurgical electric furnace provided by the above embodimentof the present disclosure, especially in a continuously operatedmetallurgical electric furnace, and particularly a metallurgicalelectric furnace operated by an open arc, the outlet of the oxygen lanceand the outlet of the coal lance are higher than the upper surface ofthe slag 3, the O₂ is blown into the slag 3 from top to bottom (alongthe direction of an arrow A in FIG. 1 and the direction of an arrow C inFIG. 2) by the oxygen lance, the low-valent reduced state substance inthe slag 3 is oxidized to a high-valent oxidation state substance, alarge amount of chemical energy is released in the oxidation process,the temperature of the slag 3 is increased, the released chemical energycan effectively smelt the feed, the coal particles is also sprayed intothe slag 3 from top to bottom (along the direction of an arrow B in FIG.1 and the direction of an arrow C in FIG. 2) through the coal lance, thecarbon in the coal particles reduces the high-valent oxidation statesubstance to a low-valent reduced state, when the high-valent oxidationstate substance is reduced by the carbon, CO is released, meanwhile, thereduction reaction needs to absorb the heat, and then the energyreleased by the oxidation of the reduced state substance is alsosupplied to the reduction reaction; in the slag 3, due to the existenceof the O₂, the O₂ may also cause a combustion reaction with the CO andC, the heat of combustion of the combustion reaction can raise thetemperature of the slag 3 so as to provide heat for the smelting of thefeed, and can also provide energy for the reduction reaction, in thisway, the chemical energy released in the oxidation reaction and theenergy released in the combustion reaction can be used for the smeltingof the feed, so that in addition to electrical energy in the smeltingprocess, the chemical energy can also provide a large amount of energyfor the smelting process, thereby improving the total power of smelting,and improving the productivity and efficiency, and it is especiallyeffective for the slag 3 with a high melting point, so that theconsumption of electric energy is reduced.

In the present solution, the oxygen lance and the coal lance are botharranged above the slag 3, the O₂ and the coal particles are blown intothe slag 3 from top to bottom, which are away from the furnace lining,so that the damage to the furnace lining is reduced, and the servicelife of the furnace lining is prevented from being shortened. As shownby the arrow A in FIG. 1, as the O₂ is from top to bottom and inclinestoward a direction away from the installation position of the oxygenlance on the side wall 11 of the furnace chamber 1, that is, thespraying direction of the O₂ faces to the opposite side of theinstallation position of the oxygen lance on the side wall 11 of thefurnace chamber 1, as shown by the arrow B in FIG. 1, the coal particlesis also from top to bottom and inclines toward the direction away fromthe installation position of the coal lance on the side wall 11 of thefurnace chamber 1, that is, the spraying direction of the coal particlesfaces to the opposite side of the installation position of the coallance on the side wall 11 of the furnace chamber 1, so that the slagflows toward the opposite side of the installation positions of theoxygen lance and the coal lance on the side wall 11 of the furnacechamber 1, but is very far away from the furnace lining, in this way,the generated turbulence is low or somewhat cancelled by one another,and the integrity of the furnace lining can be protected.

Specifically, using an example that the reduced state substance in theslag 3 is Me₂O₃, the chemical reactions occurring in the slag 3 in theoxygen blowing and coal spraying including:

Me₂O₃+0.5O₂=2MeO₂  (1)

2MeO₂+C=Me₂O₃+CO  (2)

CO+0.5O₂=CO₂  (3)

O₂+C=CO₂  (4)

After the O₂ is blown, the reaction (1) occurs, the O₂ oxidizes theMe₂O₃ into MeO₂, the oxidation reaction is an exothermic reaction, and alarge amount of chemical energy is released in the reaction for smeltingof the feed; after the coal particles is injected, the reaction (2)occurs, the carbon reduces the MeO₂ into Me₂O₃, meanwhile, releases CO,the reaction (2) is an endothermic reaction, and the chemical energyreleased in the reaction (1) is further used for providing energy forthe reaction (2) in addition to smelting the feed; and the O₂ in theslag 3 can also cause the combustion reactions (3) and (4) with the COand C, a part of the heat of combustion is released into the slag 3 forsmelting the feed and being supplied to the reaction (2), as thereaction (1), the reaction (3) and the reaction (4) are all exothermicreactions, the chemical energy released in the reactions improves thetotal smelting power and reduces the consumption of electric energy. Atthe same time, a large amount of CO is released in the reaction (2) toform bubbles, which swells the slag 3 into foam slag, and the formationof the foam slag 3 is favorable for the blowing of the O₂.

The distribution of electrodes 2 in the furnace chamber is as shown inFIGS. 1 and 2, and preferably, three electrodes are arranged in atriangle.

The electric furnace of the present disclosure is fixed, the feed issupplied unceasingly, when the molten iron reaches a certain liquidlevel, a molten metal outlet is opened to release the molten metal 4,the feed is supplied as usual, and the oxygen and coal are blown andsprayed as usual. After a certain amount of the molten metal 4 flowsout, the molten metal outlet is blocked by a blocking machine, after aperiod of time, when the slag level is too high, a slag opening isopened to discharge the slag, the feed is supplied as usual, and theoxygen and coal are blown and sprayed as usual.

Preferably, as shown in FIGS. 1 and 3, the continuously operatedmetallurgical electric furnace includes a plurality of oxygen lances andplurality of coal lances, the plurality of oxygen lances are uniformlydistributed along the side wall 11 of the furnace chamber 1; and theplurality of coal lances are uniformly distributed along the side wall11 of the furnace chamber 1.

In a specific embodiment of the present disclosure, the oxygen lancesare located below the coal lances. Preferably, the number of the oxygenlances is equal to the number of the coal lances, the coal lances arelocated right above the oxygen lances, and the two lances are arrangedup and down.

In another specific embodiment of the present disclosure, the oxygenlance and the coal lance are located at the same height on the side wall11 of the furnace chamber 1 and are arranged on the left and rightsides.

Preferably, as shown in FIG. 2, the plurality of oxygen lances areuniformly distributed at the same height on the side wall 11 of thefurnace chamber 1 along the circumferential direction, and the pluralityof coal lances are uniformly distributed at the same height on the sidewall 11 of the furnace chamber 1 along the circumferential direction.

Preferably, a coal lance and an oxygen lance can be placed in the samecooling jacket, and the distance between the injection points of thecoal lance and the oxygen lance in a molten pool is not less than 300mm.

In the above embodiment, the oxygen lance and the coal lance are locatedabove the molten pool, and the O₂ and the coal particles are blown intothe furnace chamber 1 from top to bottom, the flow rate of the O₂ is asupersonic speed to penetrate through the foam slag, and the coal canalso be injected into the molten pool. The plurality of oxygen lancesare uniformly distributed on the side wall 11 of the furnace chamber 1,so that the uniformity of blowing the O₂ into the slag 3 can beimproved, in this way, the distribution uniformity of the chemicalenergy released by the reduced state substance in the oxidation processin the slag 3 is improved, and the smelting uniformity of the feed inthe furnace chamber 1 is improved; and the plurality of coal lances areuniformly distributed on the side wall 11 of the furnace chamber 1, sothat the uniformity of spraying the coal particles into the slag 3 isimproved, and the conversion rate of reducing the high-valent oxidationstate substance into the low-valent reduced state substance is improved.

Preferably, the oxygen lance and the coal lance are installed on theside wall 11 of the furnace chamber 1 and penetrate through a refractorymaterial to enter the furnace chamber 1.

Preferably, as shown in FIG. 3, the continuously operated metallurgicalelectric furnace further includes a spray tube, the spray tube islocated on the side wall 11 of the furnace chamber 1 and used forspraying a hydrocarbon into a furnace freeboard, wherein the outlet ofthe spray tube is higher than the slag 3.

In the above embodiment, a part of the electrical energy and thechemical energy is applied to the reaction (2), the CO produced by thereaction (2) enters the furnace freeboard, and the CO carries a largeamount of energy, a part of the heat of combustion released by thereactions (3) and (4) is used for smelting the feed and the reaction(2), a part of the heat of combustion heats up gases (CO, CO₂, O₂) andenters the furnace freeboard to serve as a heat source for the pyrolysisgasification of the hydrocarbon to generate coal gas, therefore thepresent disclosure improves the total power of the smelting, andmeanwhile, generates the coal gas, and avoids the waste of energycontained in the flue gas.

The furnace freeboard is also known as a freeboard, which refers to aspace above the molten pool and below a furnace roof.

Specifically, the hydrocarbon causes the following reactions in thefurnace freeboard:

C_(n)H_(m) =nC+m/2H₂  (5)

2C_(n)H_(m)+CO₂=2(n+1)CO+mH₂  (6)

C_(n)H_(m) +nH₂O=nCO+(n+m/2)H₂  (7)

C+CO₂=2CO  (8)

C+H₂O=H₂+CO  (9)

As the space of the furnace freeboard is limited, the reactions (5),(6), (7), (8), (9) may not reach chemical equilibrium, and the finaltemperature and gas composition depend on the dynamic balance of thesystem.

Preferably, as shown in FIG. 3, the spraying direction of thehydrocarbon into the furnace freeboard can be (but not limited to)tangential to the side wall 11 of the furnace chamber 1. Preferably, thehydrocarbon is sprayed from top to bottom (along the direction of anarrow D in FIG. 3). The spraying direction of the hydrocarbon into thefurnace freeboard is tangential to the side wall 11 of the furnacechamber 1, so that the time of the gas to staying in the furnace chamber1 is prolonged to cause more reactions. But if the location occupied bythe spray tube is too large, the design is affected, the spray tube canalso be vertical to the side wall 11 of the furnace chamber 1, that is,the spraying direction of the hydrocarbon into the furnace freeboard isvertical to the side wall 11 of the furnace chamber 1.

Preferably, a plurality of uniformly distributed spray tubes is arrangedon the side wall 11 of the furnace chamber 1.

The embodiment of the second aspect of the present disclosure provides asmelting method for the metallurgical electric furnace according to anyone of the above embodiments, wherein the slag 3 includes a reducedstate substance capable of being oxidized by O₂, and the smelting methodincludes: blowing oxygen into the slag 3 via an oxygen lance so as tooxidize the reduced state substance to an oxidization state substance;and spraying coal into the slag 3 through a coal lance so as to reducethe oxidized oxidization state substance.

According to the smelting method provided by the above embodiment of thepresent disclosure, the O₂ is blown into the slag 3 from top to bottom(along the direction of the arrow A in FIG. 1 and the direction of thearrow C in FIG. 2) to oxidize the low-valent reduced state substance inthe slag 3 into a high-valent oxidation state substance, a large amountof chemical energy is released in the oxidation process to effectivelysmelt the slag, meanwhile, the coal particles is also sprayed into theslag 3 from top to bottom (along the direction of the arrow B in FIG. 1and the direction of the arrow C in FIG. 2) to reduce the high-valentoxidation state substance to a low-valent reduced state, CO is releasedat the same time, the reduction reaction is an endothermic reaction, theenergy released by the oxidation of the reduced state substance is alsosupplied to the reduction reaction; and in the slag 3, the O₂ has acombustion reaction with the CO and C, the heat of combustion of thecombustion reaction can raise the temperature of the slag 3 so as toprovide heat for the smelting of the feed, and can also provide energyfor the reduction reaction, in this way, the chemical energy released inthe oxidation reaction and the energy released in the combustionreaction can be used for the smelting of the feed, in addition toelectrical energy in the smelting process, the chemical energy can alsoprovide a large amount of energy for the smelting process, therebyimproving the total power of smelting, and improving the productivityand efficiency, it is especially effective for the slag 3 with a highmelting point, and the consumption of electric energy is reduced.

Preferably, the depth of the oxygen blown into the slag 3 does notexceed one-half of the thickness of the slag 3. Thus, a high oxidationarea, namely, a high reaction area, is located at the upper part of theslag 3, the lower part is not affected by the blowing and spraying andis still a high reduction area, so that the recovery of the metal is notaffected.

Of course, the oxygen can be firstly blown and then the coal is sprayed,and the oxygen blowing and coal spraying can be performed at the sametime.

In the above technical solution, preferably, the depth of the oxygenblown into the slag 3 is within the range of one-third of the thicknessof the slag 3 to one-half of the thickness of the slag 3.

In the above embodiment, for different slag 3 systems, the ratios of thedepth of O₂ blown into the slag 3 to the total thickness of the slag 3are different, if the slag 3 system needs to be controlled at a very lowoxygen potential to reduce the metal oxides to be recycled, the depth ofthe oxygen blown into the slag 3 is within the range of one-third of thelongitudinal thickness of the slag 3 to two-thirds of the longitudinalthickness of the slag 3, and the coal particles can be sprayed deeper toensure the low oxygen potential.

Preferably, the coal is anthracite or bituminous coal.

In the electric arc furnace steelmaking, only the anthracite or coke canbe used, and the bituminous coal cannot be used. However, the anthraciteor bituminous coal can be used in the present application. Of course,the coke can also be used in the present application. Because in thesteelmaking furnace, the purpose is to generate enough gas (CO) to causefoam slag, but to avoid generating too much gas, which leads to theconsumption of excessive oxygen, and the excessive gas generated cannotbe recycled at the same time, resulting in waste, so the use ofbituminous coal in the steelmaking furnace is avoided. However, in thepresent disclosure, the gas yield is increased and the gas is completelyrecycled, so bituminous coal is another choice, and accordingly, theproduction cost can be reduced.

Preferably, after spraying the coal into the slag 3 through the coallance, the method further includes: blowing a hydrocarbon into thefurnace freeboard through a spray tube.

In the above embodiment, the hydrocarbon is blown into the furnacefreeboard horizontally into the furnace freeboard (along the directionof the arrow D or straight to the center in FIG. 3), the energy carriedby the CO released by the oxidation reaction, the chemical energygenerated by the combustion reaction of CO and O₂, and the chemicalenergy generated by the combustion reaction of C and O₂ can be used asthe heat source for the pyrolysis gasification of the hydrocarbon, sothat a coal gas is generated in the furnace freeboard.

Preferably, the hydrocarbon includes natural gas or light oil. Ofcourse, methane gas and solid bituminous coal and the like sprayed intothe furnace freeboard can be converted into the coal gas, thetemperature of the gases (CO+CO₂+H₂+H₂O) generated in the molten pool isextremely high (the temperature is greater than 1700° C.), and the gasescontain a large amount of heat, which enters the furnace freeboard, theabove hydrocarbon is sprayed into the furnace freeboard to cause anendothermic chemical reaction with the CO₂ and H₂O so as to cracked intothe coal gas.

Of course, the hydrocarbon can also be blown into the furnace freeboardwhile the coal is sprayed.

Preferably, while spraying the hydrocarbon into the furnace freeboardthrough the spray tube, the method further includes: spraying liquidwater and/or gaseous water into the furnace freeboard through the spraytube.

In the above embodiment, in order to increase the content of hydrogen inthe coal gas, a small amount of water may be sprayed while spraying thehydrocarbon. Of course, an additional spray tube can also be arranged onthe side wall of the furnace chamber for spraying the water. Withrespect to the spraying sequence of the liquid water and/or the gaseouswater and the hydrocarbon, the water can be sprayed while blowing thehydrocarbon, or can be sprayed successively. Specifically, thehydrocarbon can be sprayed at first and the water can also be sprayed atfirst.

Using the smelting of titanium vanadium magnetite as an example, theoxygen blowing and coal spraying is carried out in a pilot electricfurnace, and the operating parameters are different according to theconditions of the raw materials. The table below lists some operationparameters of two different smelting manners and the obtained ironoutput, coal gas output and coal gas components.

Embodiment — First Second embodiment embodiment Raw material — Directcold Prereduction hot feeding feeding Metallization rate % 0 85 Inlettemperature ° C. 25 650 Iron output tph 1.2 2.9 Slag output tph 0.8 1.9Electric power MW 2.4 1.9 Chemical energy power MW 4.1 4.6 Total powerMW 6.5 6.5 Oxygen blowing amount Nm³/h 1435 1607 Natural gas sprayingamount Nm³/h 323 354 Bituminous coal spraying tph 2.0 2.2 amountAnthracite adding amount tph 0.59 0.35 Nitrogen consumption Nm³/h 198222 Electric furnace flue gas flow Nm³/h 6302 6394 CO Vol % 59 57 H₂ Vol% 29 30 N₂ Vol % 7 7 CO₂ Vol % 3 4 H₂O Vol % 2 2

The first embodiment differs from the second embodiment in that, in thefirst embodiment, the cold material is directly added into themetallurgical electric furnace, and in the second embodiment, thevanadium titano-magnetite is pre-reduced to a high metallization rate,and then the hot material is added into the metallurgical electricfurnace.

It can be seen from the parameters of the first embodiment and thesecond embodiment that after the oxygen blowing and coal sprayingtechnology is adopted in the metallurgical electric furnace, theelectric power accounts for 37% of the total power in the firstembodiment, and the electric power accounts for 30% of the total powerin the second embodiment, therefore, after the oxygen blowing and coalspraying technology is adopted, the consumption of electric energy isreduced in the smelting.

In the first embodiment and the second embodiment, the total power isthe same, and the coal gas output and the components generated are alsosubstantially the same, but the iron output produced in the secondembodiment is 2.4 times greater than that of the first embodiment. Inthe first embodiment, the cold material is directly added and is notpre-reduced, so that the equipment is simple, and the investment issmall, but the total energy consumption per ton of finished product islarge, and the dosage of the anthracite used as a reducing agent islarge. In the second embodiment, the pre-reduced hot material requiresthe investment of pre-reduction equipment, but the cheap bituminous coalcan be used as a fuel and the reducing agent to reduce the dosage of theanthracite, and the smelting energy consumption is small. In the actualusing process, the choice of direct addition of the cold material or theaddition of the pre-reduced hot material can depend on the energy price.

It should be noted that the solution is mainly for the smelting ofvanadium, titanium and iron ore. At this time, the oxidation statesubstance in the reactions (1) and (2) is TiO₂, and the reduced statesubstance is Ti₂O₃, but it can also be applied to the smelting ofFeO/Fe₃O₄ systems with the presence of copper sulfide and nickel sulfideores.

In summary, the continuously operated metallurgical electric furnaceprovided by the embodiment of the present disclosure adopts the oxygenblowing and coal spraying technology, the O₂ oxidizes the low-valentreduced state substance in the slag 3 into the high-valent oxidationstate substance, the chemical energy released in the oxidation processcan effectively smelt the feed, and meanwhile, the coal particles isalso sprayed into the slag 3 from top to bottom to reduce thehigh-valent oxidation state substance into the low-valent reduced state;the O₂ in the slag 3 causes the combustion reaction with the CO and C tofurther provide heat for the smelting of the feed, so that in additionto the electrical energy in the smelting process, the chemical energycan also provide a large amount of energy for the smelting process,thereby improving the total power of smelting, and improving theproductivity and efficiency, it is especially effective for the slag 3with a high melting point, and the consumption of electric energy isreduced.

In the description of the present disclosure, the term “plurality” meanstwo or more unless specifically stated or defined otherwise; unlessotherwise specified or stated, the terms “connection”, “fixation” andthe like are understood generally, for example, the “connection” may bea fixed connection, a detachable connection, or an integral connection,or an electrical connection; and it may be directly connected orindirectly connected through an intermediate medium. The specificmeanings of the above terms in the present disclosure may be understoodby those of ordinary in the art according to the specific conditions.

In the description of the present specification, it should be understoodthat the orientation or positional relationships indicated by the terms“upper”, “lower”, “front”, “rear”, “left”, “right” and the like areorientation or positional relationships shown in the drawings, aremerely for the convenience of describing the present disclosure andsimplifying the description, and are not intended to imply that thedevices or units referred to have specific orientations, are constructedand operated in specific orientations, and therefore are not to beconstrued as limiting the present disclosure.

In the description of the present specification, the description of theterms “one embodiment”, “some embodiments”, “specific embodiments” andthe like mean that the specific features, structures, materials orcharacteristics described in combination with the embodiments orexamples are included in at least one embodiment or example of thepresent disclosure. In the present specification, the schematicexpressions of the above terms do not necessarily refer to the sameembodiment or example. Furthermore, the particular features, structures,materials or characteristics described may be combined in a suitablemanner in any one or more embodiments or examples.

The above descriptions are only preferred embodiments of the presentdisclosure, and are not intended to limit the present disclosure, andvarious modifications and changes can be made to the present disclosurefor those skilled in the art. Any modifications, equivalentsubstitutions, improvements and the like made within the spirit andprinciple of the present disclosure shall fall within the protectionscope of the present disclosure.

1. A metallurgical electric furnace, comprising: a furnace body providedwith a furnace chamber; an oxygen lance located on a side wall of thefurnace chamber and used for blowing oxygen into slag promoting thesmelting process, wherein the outlet of the oxygen lance is higher thanthe slag; and a coal lance located on the side wall of the furnacechamber beside the oxygen lance and used for injecting coal particlesinto the slag, wherein the outlet of the coal lance is higher than theslag.
 2. The metallurgical electric furnace according to claim 1,comprising: a plurality of oxygen lances that are uniformly distributedalong the side wall of the furnace chamber; and an equal number of coallances that are uniformly distributed along the side wall of the furnacechamber, wherein the oxygen lances are located below the coal lances, orthe oxygen lances and the coal lances are located at the same height onthe side wall of the furnace chamber.
 3. The metallurgical electricfurnace according to claim 1, further comprising: a spray tube locatedon the side wall of the furnace chamber and used for spraying ahydrocarbon into a furnace freeboard, wherein the outlet of the spraytube is higher than the slag.
 4. The metallurgical electric furnaceaccording to claim 3, wherein the spraying direction of the hydrocarboninto the furnace freeboard can be (but not limited to) tangential to theside wall of the furnace chamber.
 5. A smelting method for themetallurgical electric furnace comprising: a furnace body provided witha furnace chamber; an oxygen lance located on a side wall of the furnacechamber and used for blowing oxygen into slag promoting the smeltingprocess, wherein the outlet of the oxygen lance is higher than the slag;and a coal lance located on the side wall of the furnace chamber besidethe oxygen lance and used for injecting coal particles into the slag,wherein the outlet of the coal lance is higher than the slag, whereinthe slag comprises a reduced state substance capable of being oxidizedby oxygen, and the smelting method comprises: blowing oxygen into theslag via an oxygen lance so as to oxidize the reduced state substance toan oxidization state substance; and spraying coal into the slag througha coal lance so as to reduce the oxidized oxidization state substance.6. The smelting method according to claim 5, wherein the depth of theoxygen blown into the slag does not exceed one-half of the thickness ofthe slag.
 7. The smelting method according to claim 6, wherein the depthof the oxygen blown into the slag is within the range of one-third ofthe thickness of the slag to one-half of the thickness of the slag. 8.The smelting method according to claim 5, wherein the coal is anthraciteor bituminous coal.
 9. The smelting method according to claim 5, whereinafter spraying the coal into the slag through the coal lance, the methodfurther comprises: blowing a hydrocarbon into the furnace freeboardthrough a spray tube.
 10. The smelting method according to claim 9,wherein the hydrocarbon comprises natural gas or light oil.
 11. Thesmelting method according to claim 9, wherein while spraying thehydrocarbon into the furnace freeboard through the spray tube, themethod further comprises: spraying liquid water and/or gaseous waterinto the furnace freeboard through the spray tube.